1) Technical Field of the Invention
The present invention relates to a medical lancet, and in particular, to the medical lancet made of biodegradable material such as poly lactic acid.
2) Description of Related Arts
In general, when a patient has a hypodermic injection, a needle is shot at an appropriate portion of the body such as skin and muscle to inject medicine inside the patient. Also, a diabetic uses a lancet to sample a small amount of his or her blood by stinging it on any suitable portions, e.g., at fingertip, for routine measurement of the blood sugar. The patient having such a needle or lancet pierced into the body, especially children, sometimes suffers unendurable pain or uncomfortableness. Also, a substantial area of cells around the tingled portion may often be damaged, requiring some time to be cured. Therefore, there has been long-felt desire to develop a less invasive needle and lancet, minimizing the pain (unpleasantness) experienced by the patient.
In fact, some of injection needles have been proposed with a little pain to the patient. For example, the U.S. Pat. No. 5,752,942, corresponding to the Japanese Patent Publication Application JPA 10-57490, explains the primary reason of the patient's pain that the needle point “catches” the skin or flesh as the needle is penetrating. Also, it discloses a hypodermic needle with multi-beveled point geometry so as to reduce the pain.
The present inventors has found the reason of the pain more precisely as described below, and made the invention based upon the knowledge. As the needle is penetrating into the tissue such as skin and flesh of the patient, a contacting surface between an outer surface of the needle and the tissue of the patient is increased so that the frictional force therebetween becomes greater and the peripheral cells adjacent to the needle are drawn inside deeply. To this end, the peripheral cells are extremely deformed by the physical stress due to the frictional force, and may often be burst away (collapsed) so that a pain-producing chemical mediator such as histamine and bradykinin is released within the tissue, thereby hurting the patient. Also, the peripheral cells collapsed by the physical stress extend across the substantial region, which makes more painful and less healable. As described above, the conventional needle is highly invasive to pierce the tissue of the patient.
Also, the medical lancet is used to sampling a drop of blood by stinging into the tissue at the appropriate portion of the patient's body. Thus, while there are possible drawbacks as the above-mentioned needles, it is highly desired to provide the medical lancet designed less invasive by minimizing the frictional stress to the peripheral tissue of the patient. According to the medical lancet of the present invention, it cuts the peripheral cells as few as possible and wedges away the intact tissues into the deep inside, as will be described herein in detail.
Therefore, one of the aspects of the present invention is to provide a less invasive medical lancet giving less pain to the patient.
Meanwhile, such a needle and lancet are disposed immediately after once used, to prevent various infections. Since the conventional needle and lancet are generally made of metal, they are usually treated as industrial waste for landfill rather than as the burnable waste. However, it now raises a serious social problem because of the huge amount of the industrial waste and the risk of the infections thereby.
Therefore, another one of the aspects of the present invention is to provide the medical lancet integrally formed of biodegradable material such as Poly Lactic Acid, which can be degraded by micro-organisms once deposited in the soil.